Project Summary Pressure injuries are a serious health care problem and affect millions of people. Most pressure injuries are avoidable with the application of best practices and with the use of appropriate technology. Support surfaces are a crucial component of any comprehensive prevention strategy. Decades of research have produced moderate and low levels of evidence upon which to base clinical decisions concerning how and when to apply support surfaces for prevention. This knowledge has been periodically assessed and assembled into clinical practice guidelines. There is good evidence that the combined group of active and reactive support surfaces is effective in preventing pressure injuries and that high-specification reactive foam surfaces are effective in preventing pressure injuries. But there is insufficient evidence that low air loss surfaces are more or less effective than other types of surfaces. Yet, low air loss surfaces are used for more than 17% of patients in acute care at high risk of developing pressure injuries. Our study is designed to determine if and when low air loss is effective in preventing pressure injuries, and what level of heat and moisture control performance is necessary for prevention effectiveness. The primary aim of the project is to compare the effectiveness of reactive support surfaces with low air loss to reactive support surfaces without low air loss in preventing pressure injuries for people with moisture risk factors in acute care. Support surfaces are currently marketed and identified by practitioners based on device features (e.g., low air loss, air fluidization, alternating pressure), categories (powered, non-powered, reactive, and active) and components (e.g., foam, gel, fluid). A WOCN developed selection algorithm specifies support surfaces based on categories and features. The critical performance characteristics of low air loss systems are moisture, humidity and temperature management. Preliminary work has revealed that these characteristics vary widely among different low air loss products. A secondary aim of the proposed study is to explore associations between support surface performance characteristics and pressure injury outcomes to identify which low air loss performance characteristics and what level of those performance characteristics are necessary for the technology to be effective. Successful completion of this project will fill a critical gap in evidence regarding the effectiveness of support surfaces with low air loss, and could influence a shift in the way support surfaces are characterized away from the current feature-based paradigm toward a more clinically relevant and generalizable performance-based paradigm.